High resolution intra-operative two-dimensional specimen mammography and its impact on second operation for re-excision of positive margins at final pathology after breast conservation surgery

Analysis of Specimen Mammography with Artificial Intelligence to Predict Margin Status

BACKGROUND

Intraoperative specimen mammography is a valuable tool in breast cancer surgery, providing immediate assessment of margins for a resected tumor. However, the accuracy of specimen mammography in detecting microscopic margin positivity is low. We sought to develop an artificial intelligence model to predict the pathologic margin status of resected breast tumors using specimen mammography.

METHODS

A dataset of specimen mammography images matched with pathologic margin status was collected from our institution from 2017 to 2020. The dataset was randomly split into training, validation, and test sets. Specimen mammography models pretrained on radiologic images were developed and compared with models pretrained on nonmedical images. Model performance was assessed using sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC).

RESULTS

The dataset included 821 images, and 53% had positive margins. For three out of four model architectures tested, models pretrained on radiologic images outperformed nonmedical models. The highest performing model, InceptionV3, showed sensitivity of 84%, specificity of 42%, and AUROC of 0.71. Model performance was better among patients with invasive cancers, less dense breasts, and non-white race.

CONCLUSIONS

This study developed and internally validated artificial intelligence models that predict pathologic margins status for partial mastectomy from specimen mammograms. The models' accuracy compares favorably with published literature on surgeon and radiologist interpretation of specimen mammography. With further development, these models could more precisely guide the extent of resection, potentially improving cosmesis and reducing reoperations.

Evaluating Receptor-Specific Fresh Specimen Staining for Tumor Margin Detection in Clinical Breast Specimens

PURPOSE

Reliable and rapid identification of tumor in the margins of breast specimens during breast-conserving surgery to reduce repeat surgery rates is an active area of investigation. Dual-stain difference imaging (DDSI) is one of many approaches under evaluation for this application. This technique aims to topically apply fluorescent stain pairs (one targeted to a receptor-of-interest and the other a spectrally distinct isotype), image both stains, and compute a normalized difference image between the two channels. Prior evaluation and optimization in a variety of preclinical models produced encouraging diagnostic performance. Herein, we report on a pilot clinical study which evaluated HER2-targeted DDSI on 11 human breast specimens.

PROCEDURES

Gross sections from 11 freshly excised mastectomy specimens were processed using a HER2-receptor-targeted DDSI protocol shortly after resection. After staining with the dual-probe protocol, specimens were imaged on a fluorescence scanner, followed by tissue fixation for hematoxylin and eosin and anti-HER2 immunohistochemical staining. Receiver operator characteristic curves and area under the curve (AUC) analysis were used to assess diagnostic performance of the resulting images. Performance values were also compared to expression level determined from IHC staining.

RESULTS

Eight of the 11 specimens presented with distinguishable invasive ductal carcinoma and/or were not affected by an imaging artifact. In these specimens, the DDSI technique provided an AUC = 0.90 ± 0.07 for tumor-to-adipose tissue and 0.81 ± 0.15 for tumor-to-glandular tissue, which was significantly higher than AUC values recovered from images of the targeted probe alone. DDSI values and diagnostic performance did not correlate with HER2 expression level, and tumors with low HER2 expression often produced high AUC, suggesting that even the low expression levels were enough to help distinguish tumor.

CONCLUSIONS

The results from this preliminary study of rapid receptor-specific staining in human specimens were consistent with prior preclinical results and demonstrated promising diagnostic potential.

Computer Vision Analysis of Specimen Mammography to Predict Margin Status

Intra-operative specimen mammography is a valuable tool in breast cancer surgery, providing immediate assessment of margins for a resected tumor. However, the accuracy of specimen mammography in detecting microscopic margin positivity is low. We sought to develop a deep learning-based model to predict the pathologic margin status of resected breast tumors using specimen mammography. A dataset of specimen mammography images matched with pathology reports describing margin status was collected. Models pre-trained on radiologic images were developed and compared with models pre-trained on non-medical images. Model performance was assessed using sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). The dataset included 821 images and 53% had positive margins. For three out of four model architectures tested, models pre-trained on radiologic images outperformed domain-agnostic models. The highest performing model, InceptionV3, showed a sensitivity of 84%, a specificity of 42%, and AUROC of 0.71. These results compare favorably with the published literature on surgeon and radiologist interpretation of specimen mammography. With further development, these models could assist clinicians with identifying positive margins intra-operatively and decrease the rate of positive margins and re-operation in breast-conserving surgery.

The Role of Calcium in Non-Invasively Imaging Breast Cancer: An Overview of Current and Modern Imaging Techniques

The landscape of breast cancer diagnostics has significantly evolved over the past decade. With these changes, it is possible to provide a comprehensive assessment of both benign and malignant breast calcifications. The biochemistry of breast cancer and calcifications are thoroughly examined to describe the potential to characterize better different calcium salts composed of calcium carbonate, calcium oxalate, or calcium hydroxyapatite and their associated prognostic implications. Conventional mammographic imaging techniques are compared to available ones, including breast tomosynthesis and contrast-enhanced mammography. Additional methods in computed tomography and magnetic resonance imaging are discussed. The concept of using magnetic resonance imaging particularly magnetic susceptibility to characterize the biochemical characteristics of calcifications is described. As we know magnetic resonance imaging is safe and there is no ionization radiation. Experimental findings through magnetic resonance susceptibility imaging techniques are discussed to illustrate the potential for integrating this technique to provide a quantitative assessment of magnetic susceptibility. Under the right magnetic resonance imaging conditions, a distinct phase variability was isolated amongst different types of calcium salts.

Effect of three-dimensional intraoperative imaging on surgical outcomes with breast conservation therapy

BACKGROUND

Breast conservation therapy (BCT) is frequently performed for breast cancer and associated with a significant risk for positive margins. Intraoperative three-dimensional (3-D) tomosynthesis potentially could limit the risk of positive margins.

METHODS

Retrospective review of an institutional breast cancer registry. Evaluated BCT cases for a two year time period prior to and after the introduction of intraoperative 3-D tomosynthesis. Primary outcome was the effect of 3-D tomosynthesis on margin positivity rates. Secondary measures were the impact of 3-D tomosynthesis on additional margin procurements at the index surgery and operative time.

RESULTS

A total of 228 cases were evaluated with 106 cases utilizing 3-D tomosynthesis and 122 cases with standard imaging. No significant difference in margin positivity rates between the cohorts at 23.9% versus 15.8% for 3-D tomosynthesis and standard imaging respectively (OR 1.53, CI 0.772-3.032, P = 0.221). 3-D tomosynthesis was associated with increased margin procurement rates (OR 2.34, 95%CI 1.303-4.190, P = 0.004) and longer operative times (P < 0.001).

CONCLUSION

Intraoperative 3-D tomosynthesis was not found to limit margin positivity rates or improve the performance of the procedure.

Specimen mammography for intraoperative margin assessment in breast conserving surgery: a meta-analysis

In breast conserving surgery (BCS), specimen mammography is one of the most widely used intraoperative methods of assessing margin status. We performed a meta-analysis to evaluate the diagnostic accuracy of specimen mammography. Literature databases including PubMed, Cochrane Library, Web of Science, and EMBASE were searched prior to Jun 2022. A total of 1967 patients were included from 20 studies. A pooled analysis, heterogeneity testing, threshold effect testing, publication bias analysis, and subgroup analyses were performed from extracted data. The pooled weighted values were a sensitivity of 0.55 (95% confidence interval [CI], 0.47-0.63), a specificity of 0.85 (95% CI, 0.78-0.90), a diagnostic odds ratio of 7 (95% CI, 4-12), and a pooled positive likelihood ratio of 3.7 (95% CI 2.6-5.5). The area under the receiver operator characteristic curve was 0.75 (95% CI 0.71-0.78). In the subgroup analysis, the pooled specificity in the positive margin defined as tumor at margin subgroup was lower than the other positive margin definition subgroup (0.82 [95% CI: 0.71, 0.92] vs. 0.87 [95% CI: 0.80, 0.94], p = 0.01). Our findings indicated that specimen mammography was an accurate intraoperative imaging technique for margin assessment in BCS.

Diagnostic accuracy of radiography, digital breast tomosynthesis, micro-CT and ultrasound for margin assessment during breast surgery: A systematic review and meta-analysis

RATIONALE AND OBJECTIVES

Achieving adequate resection margins in breast conserving surgery is challenging and often demands more than one surgical procedure. We evaluated pooled diagnostic sensitivity, and specificity of radiological methods for intraoperative margin assessment and their impact on repeat surgery rate.

MATERIALS AND METHODS

We included studies using radiography, digital breast tomosynthesis (DBT), micro-CT, and ultrasound for intraoperative margin assessment with the histological assessment as the reference method. A systematic search was performed in PubMed, Embase, Cochrane Library, Scopus, and Web of Science. Two investigators screened the studies for eligibility criteria and extracted data of the included studies independently. The quality assessment on diagnostic accuracy studies (QUADAS)-2 tool was used. A bivariate random effect model was used to obtained pooled sensitivity and specificity of the index tests in the meta-analysis.

RESULTS

The systematic search resulted in screening of 798 unique records. Twenty-two articles with 29 radiological imaging methods were selected for meta-analysis. Pooled sensitivity and specificity and area under the curve were calculated for each of the 4 subgroups in the meta-analysis respectively: Radiography; 52%, 77%, 60%, DBT; 67%, 76%, 76%, micro-CT; 68%, 69%, 72%, and ultrasound; 72%, 78%, 80%. The repeat surgery rate was poorly reported in the included studies.

CONCLUSION

Ultrasound showed the highest and radiography the lowest diagnostic performance for intraoperative margin assessment. However, the heterogeneity between studies was high and the subgroups small. The radiological methods for margin assessment need further improvement to provide reliable guidance in the clinical workflow and to prevent repeat surgeries.

Development of intraoperative assessment of margins in breast conserving surgery: a narrative review

OBJECTIVE

We intend to provide an informative and up-to-date summary on the topic of intraoperative assessment of margins in breast conserving surgery (BCS). Conventional methods as well as cutting-edge technologies are analyzed for their advantages and limitations in the hope that clinicians can turn to this for reference. This review can also offer guidance for technicians in the future design of intraoperative margin assessment tools.

BACKGROUND

Achieving negative margins during BCS is one of the vital factors for preventing local recurrence. Conducting intraoperative margin assessment can ensure negative margins to a large extent and possibly relieve patients of the anguish of re-interventions. In recent years, innovative methods for margin assessment during BCS are advancing rapidly. And there is a lack of summary regarding the development of intraoperative margin assessment in BCS.

METHODS

A PubMed search with keywords "intraoperative margin assessment" and "breast conserving surgery" was conducted. Relevant publications were screened manually for its title, abstract and even full text to determine its true relevance. Publications on neo-adjuvant therapy and intraoperative radiotherapy were excluded. References from the searched articles and other supplementary articles were also looked into.

CONCLUSIONS

Conventional methods for margin assessment yields stable outcome but its use is limited because of the demand on pathology staff and the trade-off between time and precision. Conventional imaging techniques pass the workload to radiologists at the cost of a significantly low duration of time. Involving artificial intelligence for image-based assessment is a further improvement. However, conventional imaging is inherently flawed in that occult lesions can't show on the image and the showing ones are ambiguous and open to interpretation. Unconventional techniques which base their judgment on cellular composition are more reassuring. Nonetheless, unconventional techniques should be subjected to clinical trials before putting into practice. And studies regarding comparison between conventional methods and unconventional methods are also needed to evaluate their relative efficacy.

Using a mobile device for margin assessment of specimen mammography in breast-conserving surgery

To compare the performance of margin assessment of specimen mammography (SM) in patients with breast-conserving surgery (BCS) on mobile devices and 5-megapixel (5M) thin film transistor liquid crystal display (TFT-LCD) monitors based on the safety margin for pathologic results.This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. A total of 105 consecutive breast cancer SM samples from 104 women who underwent BCS were included in the study. The SM were independently reviewed by two radiologists using mobile devices and by two additional radiologists using 5M TFT-LCD monitor. Each reader was asked to measure the shortest distance between the lesion and the lesion margin. The interpretation time was recorded. The sensitivity, specificity, and interobserver agreement were analyzed.In total, 19% (20/105) breast specimens had a positive surgical margin (<1 mm). The mean absolute difference from the pathologic margin was 0.60 ± 0.57 cm and 0.54 ± 0.47 cm using the 5 M TFT-LCD monitor and the mobile device, respectively (without any statistical significance, P = .273). The mean interpretation time was 49.5 and 47.6 s for the 5M TFT-LCD monitor and the mobile device, respectively (P = .012). The pooled sensitivity and specificity were 60% and 74% for 5M TFT-LCD monitor, and 60% and 69% for the mobile device (P = 1.00 and P = .190, respectively). The kappa coefficient indicated moderate agreement for both the displays.The diagnostic performance for margin assessment of SM in BCS patients on mobile devices and 5M TFT-LCD monitors are showed not statistically difference. The findings of the study provide evidence of the benefit of the mobile device for SM interpretation in patients who underwent BCS. However, a large sample size study is warranted before using a mobile device for margin evaluation on SM.The mobile device showed comparable diagnostic performance with 5M TFT-LCD monitor in the evaluation of SM margin in patients with BCS and could be used as a display tool for immediate assessment when a dedicated LCD monitor is unavailable.

The Impact of Advanced Image-Guided Breast Surgery and Oncoplastic Techniques on Margin Positivity in Breast Conserving Surgery

Objective 

Positive margins remain a significant psychological and economic burden after breast conserving surgery. The aim of this study was to test the hypothesis that advanced oncoplastic techniques as well as intraoperative integrative imaging with intraoperative ultrasound and mobile digital specimen radiography decreases positive margin rate in breast conserving surgery.

Methods 

A single-institution retrospective review of a prospectively collected database was performed. Patients with breast neoplasms who underwent lumpectomy with or without using intraoperative integrative imaging approaches and oncoplastic techniques were included. The primary outcome was positive margin rate for each technique.

Results 

A total of 392 patients were included in the study. The median age of the cohort was 59 years. Overall positive margin rate was 15%. Ductal carcinoma in situ (DCIS) histology and larger tumor size were associated with higher positive margin rate. Intraoperative integrative imaging significantly decreased positive margin rate (9% vs. 18%, p=0.018). Oncoplastic techniques also decreased positive margin rate from 16% to 12%, however this was not significant.

Conclusion 

Positive margin rate was significantly lower when intraoperative integrative imaging was used. Oncoplastic techniques also decreased positive margin rate in a selected group of patients with large tumor size. We suggest incorporating these techniques in all breast conserving surgery cases.

Is specimen radiography still necessary in patients with non-palpable breast cancer undergoing breast-conserving surgery using radioactive I-125 seed localization?

AIM

To evaluate the diagnostic performance for margin assessment of specimen radiography (SR) in breast conserving surgery (BCS) using radioactive I¹²⁵-seed localization (RSL).

METHODS

The clinical, radiographic and histopathological data of women who underwent BCS after pre-operative RSL with intraoperative SR during nine consecutive years were analyzed. The histological margin and radiographic margin outcomes on SR were compared and results of intraoperative re-excisions were investigated.

RESULTS

A consecutive series of 448 women with invasive carcinoma (n = 211), ductal carcinoma in situ (DCIS) (n = 79) and a combination of DCIS and invasive carcinoma (n = 158) were included. The median minimal margins for the radiological masses and microcalcifications measured on SR were 14 mm and 11 mm, respectively. Based on a radiological cut-off SR margin value of 1 mm, the overall sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were 21.0%, 95.0%, 26.0%, and 94.0%, respectively. The area under the receiver-operating curve was 0.73. Intraoperative re-excisions based on SR were performed in 31 (6.9%) patients; histopathological examination of the additional excised tissue revealed DCIS or invasive carcinoma in 6 (19.4%) patients. Hence, SR was beneficial for 6/448 patients (1.3%), and unnecessary intraoperative re-excisions were performed in 20/448 patients (4.5%). The number need to treat is 75; this implies that per 75-SR one resection with involved margins is prevented.

CONCLUSION

SR has a moderate diagnostic performance for margin involvement using RSL. A more accurate intraoperative margin assessment tool is warranted.

Vacuum intraoperative specimen mammography: A novel technique

OBJECTIVE

Intraoperative specimen mammography (ISM) is a diffuse technique that allows surgeons to check specimens immediately after lumpectomy. Although the specimen is slightly compressed, the radiological image can be distorted by tissue overlap, and this may affect the evaluation of tumour borders, resulting in extension of the lumpectomy. As ISM may be less precise due to inadequate compression, a vacuum effect was applied to the specimen to increase the precision of margin detection.

STUDY DESIGN

This study was conducted at St. Anna Hospital Breast Unit, Turin, Italy. Women who underwent lumpectomy for cancer were eligible for inclusion. Both standard ISM (sISM) and vacuum ISM (vISM) were performed. Eighteen specimens obtained after lumpectomy from 1 April 2018 to 31 April 2018 were scanned. sISM (two orthogonal projections) was performed. Next, the specimen was placed in a vacuum, and vISM was performed. The examination was completed with a second orthogonal projection after removal of the vacuum, replacement of the specimen and repositioning of the vacuum. Additional tissue was removed if the surgeon considered that excision was inadequate. Finally, the specimen was sent for definitive histopathological analysis, which is the gold standard for the assessment of surgical margins. Intraoperative histological margin assessment was not performed. The sISM and vISM images and final histopathology reports were compared.

RESULTS

For sISM, specificity was 47 % [95 % confidence interval (CI) 25-70], sensitivity was 67 % (95 % CI 21-94), positive predictive value (PPV) was 20 % (95 % CI 6-51) and negative predictive value (NPV) was 88 % (95 % CI 53-98). For vISM, specificity was 100 % (95 % CI 80-100), sensitivity was 67 % (95 % CI 21-94), PPV was 100 % (95 % CI 34-100) and NPV was 94 % (95 % CI 72-99).

CONCLUSION

These data suggest that the vacuum technique is feasible, cost-saving and yields results that are similar to those from frozen sections but without the limitations, such as prolonged operating time, high variability in sensitivity due to pathologists' abilities, risk of compromising the histological report, and unreliability for small lumps and ductal carcinoma in situ.

Differences in Re-excision Rates for Breast-Conserving Surgery Using Intraoperative 2D Versus 3D Tomosynthesis Specimen Radiograph

BACKGROUND

Intraoperative specimen radiographs performed during breast conservation surgery for cancer reduces the need for re-excision for positive margins. We studied 2D versus 3D image-guided cavity margin excision and compared it to final pathology and need for additional surgery.

METHODS

We conducted a retrospective review of 657 breast-conserving operations performed for cancer from 2013 to 2018. Procedures were performed by four surgeons at a single tertiary institution with access intraoperatively to 2D and 3D radiographs. Data collected included demographics, intraoperative margin assessment, final pathology, and re-excision rates.

RESULTS

A total of 466 patients had 2D and 191 had 3D specimen imaging. The 2D group had a lower mean age and a higher body mass index and proportion of minority patients than the 3D group (P < 0.01). In the 3D group, there was a higher percentage of patients with mammographically denser breasts (P < 0.06); 58% of patients in the 3D group had additional imaging-directed cavity margins excised versus 32% of patients in the 2D group (P < 0.01). In the 2D group, 44 patients (9%) had positive final margins versus 8 patients (4%) in the 3D group (P = 0.02). No difference was found on total volume of excision (P = 0.56). The re-excision rate for the 2D group was 11% versus 5% for the 3D group (P = 0.02; adjusted odds ratio = 0.41, 95% confidence interval 0.19-0.86).

CONCLUSIONS

Re-excision rates using both modalities are low. A lower re-excision rate is independently associated with 3D tomosynthesis. This allows surgeons to excise additional margins at the index operation, decreasing reoperations and anxiety/costs for patients.

High-Frequency Ultrasonic Forceps for the In Vivo Detection of Cancer During Breast-Conserving Surgery

A major aim in the surgical management of soft tissue cancers is to detect and remove all cancerous tissues while ensuring noncancerous tissue remains intact. Breast-conserving surgery provides a prime illustration of this aim, since remaining cancer in breast margins results in multiple surgeries, while removal of too much unaffected tissue often has undesirable cosmetic effects. Similarly, resection of benign lymph nodes during sentinel lymph node biopsy can cause deleterious health outcomes. The objective of this study was to create an intraoperative, in vivo device to address these challenges. Instant diagnostic information generated by this device could allow surgeons to precisely and completely remove all malignant tissue during the first surgery. Surgical forceps based on Martin forceps were instrumented at the tips with high-frequency ultrasonic transducers composed of polyvinylidene difluoride, a thickness-sensing rotary potentiometer at the base, and a spring to provide the appropriate restoring force. Transducer wires within the forceps were connected to an external high-frequency pulser-receiver, activating the forceps' transmitting transducer at 50 MHz and amplifying through-transmission signals from the receiving transducer. The forceps were tested with tissue-mimicking agarose phantoms embedded with 58–550 μm polyethylene microspheres to simulate various stages of cancer progression and to provide a range of measurement values. Results were compared with measurements from standard 50 MHz immersion transducers. The results showed that the forceps displayed similar sensitivity for attenuation and increased accuracy for wave speed. The forceps could also be extended to endoscopes and laparoscopes.

Evaluation of 2014 margin guidelines on re-excision and recurrence rates after breast conserving surgery: A multi-institution retrospective study

Introduction

A 2014 consensus statement from the Society of Surgical Oncology and American Society for Radiation Oncology supported “no ink on tumor” as an adequate margin for breast conserving therapy (BCT). This study evaluates this statement in a multi-institution cohort.

Methods

A retrospective review of BCT cases at 3 comprehensive cancer centers was performed. Women age >18 receiving BCT for T1-2 breast cancer from 2008-2012 were included. Pre-2014, all sites considered 2 mm adequate. Estimated re-excision rates using the 2014 guidelines were calculated and factors predictive of re-excision were analyzed.

Results

542 patients (545 lumpectomies) were eligible. Using a ≥2 mm margin standard, 32.8% of patients underwent re-excision compared to 14.1% after 2014 (p < 0.0001). Tumor size (p= 0.003), grade (p=0.015), and lymphovascular invasion (p=0.021) were predictive of re-excision. Patients with additional intraoperative margins excised were less likely to require reoperation (p=0.002). Local recurrence was unaffected by re-excision after mean followup of 66 months.

Conclusions

The 2014 margin guidelines markedly reduce re-excision rates. There is no difference in local recurrence for patients after re-excision for a close margin versus without Powered.

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Multi-institution review 2014 consensus statement on margins for invasive breast cancer.

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Pooled results demonstrated a 32.8% re-excision rate reduced to 14.1% if the "no tumor on ink" guidelines were applied.

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No difference in local recurrence rates, including patients with close margins, after median followup of 67 months.

Intraoperative Specimen Mammography for Margin Assessment in Breast-Conserving Surgery

The purpose of this study aimed to determine whether intraoperative specimen mammography is an effective margin assessment method in Asian women. Thus, 182 patients who underwent breast-conserving surgery (BCS) were evaluated. After wide excision, intraoperative specimen mammography was used to assess margin adequacy. The control group comprised 84 patients who underwent BCS and were evaluated for margin of frozen section during surgery. 61.6% patients had dense breasts and 85.7% of dense breasts could margin assess by intraoperative specimen mammography. There were no significant differences in the incidence of extremely close margins (p = 0.421) and second operation (p = 0.252) between both groups. Significant correlations were found between radiological and histological margins (R² = 0.222, p < 0.05). The frozen section analysis group had longer operative time than the specimen mammography group. The study results show that intraoperative specimen mammography of breast lesions in BCS is useful in identifying margin clearance.

Intraoperative Radiographic Assessment of Bone Resection Margins During Mandibulectomy: A Case Series

BACKGROUND AND PURPOSE

Mandibulectomy remains the treatment of choice for oral cavity squamous cell carcinoma with infiltration of bone and for benign tumors with full mandibular thickness involvement. Although bone resection margins are critical for patient outcomes, intraoperative immediate bone margins assessment is inadequate, and few alternative options have been described. The purpose of this study was to describe the use of an existing intraoperative radiographic system for objective determination of bone resection margins during mandibulectomy.

METHODS

We conducted a retrospective case series of all patients at the Greater Baltimore Medical Center who underwent mandibulectomy and received intraoperative Faxitron radiography from January 1, 2016, to March 1, 2019. Patient characteristics including age, sex, diagnosis, tumor location, clinical and pathologic stage, procedure performed, and bone resection margins were reviewed.

RESULTS

A total of 10 patients underwent mandibulectomy with intraoperative radiography. Nine (90%) received surgery for squamous cell carcinoma, with 1 (10%) for ameloblastoma. Out of those with squamous cell carcinoma, tumor location varied, and all were clinically stage T4. Final pathologic margins were negative in all cases (10/10), though in 2 cases, close margins were assessed intraoperatively, leading to further resection or change in operative plan.

CONCLUSION

Intraoperative radiographic assessment of bone resection margins is a promising technique, though further validation is required.

Real-time electromagnetic navigation for breast-conserving surgery using NaviKnife technology: A matched case-control study

Breast-conserving surgery (BCS) is a mainstay in breast cancer treatment. For nonpalpable breast cancers, current strategies have limited accuracy, contributing to high positive margin rates. We developed NaviKnife, a surgical navigation system based on real-time electromagnetic (EM) tracking. The goal of this study was to confirm the feasibility of intraoperative EM navigation in patients with nonpalpable breast cancer and to assess the potential value of surgical navigation. We recruited 40 patients with ultrasound visible, single, nonpalpable lesions, undergoing BCS. Feasibility was assessed by equipment functionality and sterility, acceptable duration of the operation, and surgeon feedback. Secondary outcomes included specimen volume, positive margin rate, and reoperation outcomes. Study patients were compared to a control group by a matched case-control analysis. There was no equipment failure or breach of sterility. The median operative time was 66 (44-119) minutes with NaviKnife vs 65 (34-158) minutes for the control (P = .64). NaviKnife contouring time was 3.2 (1.6-9) minutes. Surgeons rated navigation as easy to setup, easy to use, and useful in guiding nonpalpable tumor excision. The mean specimen volume was 95.4 ± 73.5 cm³ with NaviKnife and 140.7 ± 100.3 cm³ for the control (P = .01). The positive margin rate was 22.5% with NaviKnife and 28.7% for the control (P = .52). The re-excision specimen contained residual disease in 14.3% for NaviKnife and 50% for the control (P = .28). Our results demonstrate that real-time EM navigation is feasible in the operating room for BCS. Excisions performed with navigation result in the removal of less breast tissue without compromising postive margin rates.

The Impact of Margin Status on Breast Conservation Rates

BACKGROUND

Contemporary data indicate that breast conservation treatment (BCT) results in superior survival outcomes compared with mastectomy. However, positive margins after lumpectomy have implications for local control, and re-excisions are recommended to achieve negative margins. The need for reoperations after an initial attempt at BCT is associated with higher chance of conversion to mastectomy. Achieving negative margins at the first therapeutic surgical procedure is therefore critical to optimise BCT rates and survival outcomes.

METHODS

A compilation of scientific reports on BCT, margin status, rates of reoperation, and the impact on BCT rates was reviewed. Re-excision rates after initial lumpectomy is variable to a staggering degree and reported to be between 0 and 100%. High reoperation rates (ROR) are associated with higher likelihood of conversion to mastectomy, which may not confer favourable treatment outcomes. Although widely agreed that decreasing ROR is a desirable objective, there is controversy regarding the need for its urgent implementation as a quality metric. Critics of this cite challenges related to how this can be achieved and its attendant ramifications. On the other hand, without the appropriate incentive for quality improvement of surgical treatment of breast cancer, patients may be subject to poorer overall outcomes.

DISCUSSION

Techniques and approaches are discussed in this article to enable a reduction in positive margin status, and therefore ROR. The rationale for achieving ROR of 10-20% are explicated, as well as the impact this would have on BCT rates, which translates to better survival outcomes for women with breast cancer.

Lumpectomy Specimen Radiography: Does Orientation or 3-Dimensional Tomosynthesis Improve Margin Assessment?

Purpose

Our purpose was twofold. First, we sought to determine whether 2 orthogonal oriented views of excised breast cancer specimens could improve surgical margin assessment compared to a single unoriented view. Second, we sought to determine whether 3D tomosynthesis could improve surgical margin assessment compared to 2D mammography alone.

Materials and Methods

Forty-one consecutive specimens were prospectively imaged using 4 protocols: single view unoriented 2D image acquired on a specimen unit (1VSU), 2 orthogonal oriented 2D images acquired on the specimen unit (2VSU), 2 orthogonal oriented 2D images acquired on a mammogram unit (2V2DMU), and 2 orthogonal oriented 3D images acquired on the mammogram unit (2V3DMU). Three breast imagers randomly assessed surgical margin of the 41 specimens with each protocol. Surgical margin per histopathology was considered the gold standard.

Results

The average area under the curve (AUC) was 0.60 for 1VSU, 0.66 for 2VSU, 0.68 for 2V2DMU, and 0.60 for 2V3DMU. Comparing AUCs for 2VSU vs 1VSU by reader showed improved diagnostic accuracy using 2VSU; however, this difference was only statistically significant for reader 3 (0.73 vs 0.63, P = .0455). Comparing AUCs for 2V3DMU vs 2V2DMU by reader showed mixed results, with reader 1 demonstrating increased accuracy (0.72 vs 0.68, P = .5984), while readers 2 and 3 demonstrated decreased accuracy (0.50 vs 0.62, P = .1089 and 0.58 vs 0.75, P = .0269).

Conclusions

2VSU showed improved accuracy in surgical margin prediction compared to 1VSU, although this was not statistically significant for all readers. 3D tomosynthesis did not improve surgical margin assessment.

Micro-computed tomography enables rapid surgical margin assessment during breast conserving surgery (BCS): correlation of whole BCS micro-CT readings to final histopathology

Background

Roughly 23% of breast conserving surgery (BCS) patients undergo a second re-excision procedure due to pathologically positive surgical margins. We investigated the feasibility and potential value of micro-Computed Tomography (micro-CT) as a surgical margin guidance tool during BCS.

Methods

A cohort of 32 BCS specimens was prospectively imaged with a pre-clinical micro-CT system upon arrival in the surgical pathology laboratory. Reconstructed micro-CT scans were evaluated retrospectively by an experienced breast radiologist, who provided binary determinations whether lesions extended to the specimen margin. These readings were then compared to the final pathological diagnosis and to 2D specimen radiography readings.

Results

Of the 32 specimens imaged, 28 had malignant and four had benign pathological diagnoses. Overall five (four malignant, one benign) of the 32 specimens had lesion tissue extending to the margin. For all 32 specimens, micro-CT reconstructions were calculated (< 4 min. acquisition + reconstruction time) and each specimen was volumetrically analyzed by a radiologist. Of the 28 malignant specimen readings, 18 matched the final pathological diagnosis [64%, 95 CI (47%–81%)], with a negative predictive value of 89% [95 CI (74%–96%)]. Micro-CT readings revealed changes in the tumor location and margin status as compared to single-projection radiography readings.

Conclusions

Micro-CT scanning of BCS specimens enabled margin status assessment over the entirety of the surgical surface in a clinically relevant time frame, provided additional spatial information over single-projection radiography, and may be a potentially useful BCS guidance tool.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4951-3) contains supplementary material, which is available to authorized users.

Obtaining adequate surgical margin status in breast-conservation therapy: intraoperative ultrasound-guided resection versus specimen mammography

Background and aim

The purpose of breast-conserving surgery (BCS) for women with cancer is to perform an oncological radical procedure with disease-free margins at the final histological assessment and with the best aesthetic result possible. Intraoperative resected specimen ultrasound and intraoperative resected specimen mammography may reduce the rates of positive margins and reexcision among patients undergoing conserving therapy. Our objective is to compare the two methods with the histopathological results for a preset cut off and asses which parameters can influence the positive margin status.

Method

A prospective study was performed on 83 patients who underwent breast conservation surgery for early breast cancer (pT1-3a pN0-1 M0) between 2014 and 2016. After excision the specimen was oriented in the operating room by the surgeon. Metallic clips and threads were placed on margins: one clip and the long thread at 12 o’clock, two clips and the short threads at 9 o’clock. The next step was intraoperative ultrasound assessment of the specimen. For the margins under 2 mm we performed selective margin shaving, followed by mammography to identify and document the lesion and finally histopathological examination of the specimen with reporting the gross and microscopic margins. The positive margins required re-excision or boost of radiation at the posterior or anterior margins, depending on the case.

Results

We set a cut-off at 2 mm. The sensitivity and specificity of the intraoperative margin assessment via the ultrasound method were 90.91% (95% CI 70.84–98.88%) and 67.21% (95% CI 54–78.69%) respectively. The sensitivity and specificity of the intraoperative margin assessment via the mammographic procedure were 45.45% (95% CI 24.39–67.79%) and 85.25% (95% CI 73.83–93.02%) respectively. There was positive correlation between the histopathological and intraoperative ultrasound exam (p=0.018) and negative correlation between the histopathological exam and the post-operative mammographic exam (p=0.68). We found a positive correlation between the positive margin status and age (<40), preoperative chemotherapy, intraductal carcinoma, inflammatory process around the tumor, and the immunohistochemical triple negative profile.

Conclusions

According to our results, the intraoperative ultrasound of the breast specimen for a cutt-off at 2 mm can decrease the rates of margin positivity compared to the mammographic procedure and has the potential to diminish the number of subsequent undesired re-excisions.

Factors influencing reoperation following breast-conserving surgery

BACKGROUND

Reoperation rates after breast-conserving surgery are highly variable and the best techniques for optimizing margin clearance are being evaluated. The aim was to identify the reoperation rate at our centre and identify influential factors, including a change in guidelines on margin recommendations and the introduction of in-theatre specimen X-ray.

METHODS

A retrospective review of medical records was undertaken to identify 562 patients who underwent breast conservation at The Royal Melbourne Hospital and Royal Women's Hospital between 2013 and 2015. All cases that underwent subsequent re-excision or total mastectomy were captured and factors influencing margin excision recorded.

RESULTS

Reoperation was undertaken in 19.5% of patients (110; 86 re-excisions and 24 total mastectomies). There was a reduction in reoperation rate from 25% to 17% (P = 0.01) with adoption of the margin guidelines in 2014, but no significant reduction with the introduction of in-theatre specimen X-ray in 2015 (21% versus 16%, P = 0.14). On multivariate analysis, factors that significantly influenced reoperation rates were the presence of multifocality on mammogram (odds ratio (OR): 5.3, 95% confidence interval (CI): 1.6-16.7, P < 0.01); lesion size on mammogram (OR: 2.2 per 10 mm, 95% CI: 1.4-3.6, P < 0.01); smaller excision specimen weight (OR: 0.5 per 25 g of resection, 95% CI: 0.3-0.8, P < 0.01); and pure ductal carcinoma in situ on final pathology (OR: 5.9, 95% CI: 1.9-16.7, P < 0.01).

CONCLUSION

Optimizing reoperation rates following breast-conserving surgery remains a surgical challenge, particularly in patients with in situ or multifocal disease. Adoption of international margin guidelines reduced reoperation rates at our centre; however, introduction of intraoperative specimen X-ray had no influence.

Tumor Resection Margin Definitions in Breast-Conserving Surgery: Systematic Review and Meta-analysis of the Current Literature

Worldwide, various guidelines recommend what constitutes an adequate margin of excision for invasive breast cancer or for ductal carcinoma-in-situ (DCIS). We evaluated the use of different tumor resection margin guidelines and investigated their impact on positive margin rates (PMR) and reoperation rates (RR). Thirteen guidelines reporting on the extent of a positive margin were reviewed along with 31 studies, published between 2011 and 2016, reporting on a well-defined PMR. Studies were categorized according to the margin definition. Pooled PMR and RR were determined with random-effect models. For invasive breast cancer, most guidelines recommend a positive margin of tumor on ink. However, definitions of reported positive margins in the clinic vary from more than focally positive to the presence of tumor cells within 3 to 5 mm from the resection surface. Within the studies analyzed (59,979 patients), pooled PMRs for invasive breast cancer ranged from 9% to 36% and pooled RRs from 77% to 99%. For DCIS, guidelines vary between no DCIS on the resection surface to DCIS cells found within a distance of 2 mm from the resection edge. Pooled PMRs for DCIS varied from 4% to 23% (840 patients). Given the differences in tumor margin definition between countries worldwide, quality control data expressed as PMR or RR should be interpreted with caution. Furthermore, the overall definition for positive resection margins for both invasive disease and DCIS seems to have become more liberal.

A Phantom Study of Terahertz Spectroscopy and Imaging of Micro- and Nano-diamonds and Nano-onions as Contrast Agents for Breast Cancer

THz imaging is effective in distinguishing between cancerous, healthy, and fatty tissues in breast tumors, but a challenge remains in the contrast between cancerous and fibroglandular (healthy) tissues. This work investigates carbon-based nanoparticles as potential contrast agents for terahertz imaging of breast cancer. Microdiamonds, nanodiamonds, and nanometer-scale onion-like carbon are characterized with terahertz transmission spectroscopy in low-absorption backgrounds of polydimethylsiloxane or polyethylene. The refractive index and absorption coefficients are calculated based on the measured electric fields. Nanodiamonds show little effect on the terahertz signal, microdiamonds express resonance-like, size-dependent absorption peaks, and onion-like carbon provides a uniform increase in the optical properties even at low concentration. Due to its strong interaction with terahertz frequencies and ability to be activated for selective binding to cancer cells, onion-like carbon is implemented into engineered three-dimensional breast tumor models composed of phantom tissue mimicking infiltrating ductal carcinoma surrounded by a phantom mimicking healthy fibroglandular tissue. This model is imaged using the terahertz reflection mode to examine the effectiveness of contrast agents for differentiation between the two tissue types. In both spectroscopy and imaging, a 10% concentration of onion-like carbon shows the strongest impact on the terahertz signal and holds promise as a terahertz contrast agent.

A Study of the Growth Patterns of Breast Carcinoma Using 3D Reconstruction: A Pilot Study

Lumpectomy with microscopically clear margins is a safe and effective approach for surgical management of breast carcinoma. Margins are positive for tumor in 18-50% of lumpectomies, as it is not possible to accurately determine the shape or microscopic borders of a tumor preoperatively or intraoperatively. We examined the 3D microanatomy and growth patterns of common breast carcinoma subtypes to provide guidance for lumpectomy surgery. Prospective consent was obtained for the use of excess tissue from patients undergoing lumpectomy or mastectomy for breast carcinoma. Tissue blocks from nine breast carcinomas were serially sectioned. Hematoxylin and eosin-stained slides at 100 μm intervals were scanned using a Nanozoomer (Hamamatsu, Japan) microscopic-resolution scanner. Three-dimensional reconstructions of tumors were created from scanned images using Reconstruct, open-access software. Breast carcinoma subtypes demonstrated characteristic growth patterns within breast tissue, which may have implications for lumpectomy surgery. Invasive ductal carcinomas showed a spherical shape, with a spiculated surface representing tumor cells infiltrating into surrounding parenchyma. Ductal carcinoma in situ appeared to spread along the duct system, creating dilated, tortuous, tumor-filled ducts. The invasive lobular carcinomas examined had a haphazard, linear, infiltrative growth pattern, different from the shape seen in ductal carcinomas. Our preliminary work suggests that invasive ductal and invasive lobular carcinomas appear to have distinct growth patterns in three dimensions and ductal carcinoma in situ appears to grow in a linear fashion along the duct network. The microanatomy studies described have the potential to guide refinements in breast lumpectomy technique.

Impact of intraoperative specimen mammography on margins in breast-conserving surgery

A positive resection margin is one of the most significant risk factors for local breast cancer recurrence following breast-conserving surgery (BCS). Intraoperative specimen mammography (SMMG) is routinely used to evaluate the surgical margin at our institution. The aim of the present study was to assess the adequacy of SMMG for margin assessment. The patient cohort included 174 women who underwent BCS in 2006. The sensitivity and specificity of SMMG were assessed by comparing the margins assessed by histological and radiological methods. It was also examined whether the rate of positive histological margins was decreased by re-excision following SMMG evaluation. A total of 23 false-negatives and 6 false-positives were determined by SMMG. The sensitivity and specificity of SMMG margin assessment for patients with primary breast cancer were 20.6 and 94.6%, respectively. The positive predictive value was 50% and the negative predictive value was 82.2%. A subgroup analysis revealed that the sensitivity and specificity of SMMG in cases with ductal carcinoma in situ (DCIS) were higher compared with those in invasive ductal carcinoma. Furthermore, the positive histological margin rate was not affected by re-excision. Although the general usefulness of intraoperative SMMG was not proven, this procedure may be useful in specific cases, particularly those with DCIS and those diagnosed by stereotactic biopsy. A prospective study with exact criteria and a standard procedure is required.

Comparison of intra-operative specimen mammography to standard specimen mammography for excision of non-palpable breast lesions: a randomized trial

Standard specimen mammography (SSM) is performed in the radiology department after wire-localized excision of non-palpable breast lesions to confirm the presence of the target and evaluate margins. Alternatively, intra-operative specimen mammography (ISM) allows surgeons to view images in the operating room (OR). We conducted a randomized study comparing ISM and SSM. Women undergoing wire-localized excision for breast malignancy or imaging abnormality were randomized to SSM or ISM. For SSM, the specimen was transported to the radiology department for imaging and interpretation. For ISM, the specimen was imaged in the OR for interpretation by the surgeon and sent for SSM. Interpretation time was from specimen leaving OR until radiologist interpretation for SSM and from placement in ISM device until surgeon interpretation for ISM. Procedure and interpretation times were compared. Concordance between ISM and SSM for target and margins was evaluated. 72 patients were randomized, 36 ISM and 36 SSM. Median procedure times were similar, 48.5 (17-138) min for ISM, and 54 (17-40) min for SSM (p = 0.72), likely since specimens in both groups traveled to radiology for SSM. Median interpretation time was significantly shorter with ISM, 1 (0.5-2.0) and 9 (4-16) min for ISM and SSM, respectively (p < 0.0001). Among specimens with ISM and SSM, concordance was 100 % (35/35) for target and 93 % (14/15) for margins. In this randomized trial, use of ISM compared with SSM significantly reduced interpretation times, while accurately identifying the target. This could result in decreased operative costs from shorter OR times with use of ISM.

Toolbox to Reduce Lumpectomy Reoperations and Improve Cosmetic Outcome in Breast Cancer Patients: The American Society of Breast Surgeons Consensus Conference

BACKGROUND

Multiple recent reports have documented significant variability of reoperation rates after initial lumpectomy for breast cancer. To address this issue, a multidisciplinary consensus conference was convened during the American Society of Breast Surgeons 2015 annual meeting.

METHODS

The conference mission statement was to "reduce the national reoperation rate in patients undergoing breast conserving surgery for cancer, without increasing mastectomy rates or adversely affecting cosmetic outcome, thereby improving value of care." The goal was to develop a toolbox of recommendations to reduce the variability of reoperation rates and improve cosmetic outcomes. Conference participants included providers from multiple disciplines involved with breast cancer care, as well as a patient representative. Updated systematic reviews of the literature and invited presentations were sent to participants in advance. After topic presentations, voting occurred for choice of tools, level of evidence, and strength of recommendation.

RESULTS

The following tools were recommended with varied levels of evidence and strength of recommendation: compliance with the SSO-ASTRO Margin Guideline; needle biopsy for diagnosis before surgical excision of breast cancer; full-field digital diagnostic mammography with ultrasound as needed; use of oncoplastic techniques; image-guided lesion localization; specimen imaging for nonpalpable cancers; use of specialized techniques for intraoperative management, including excisional cavity shave biopsies and intraoperative pathology assessment; formal pre- and postoperative planning strategies; and patient-reported outcome measurement.

CONCLUSIONS

A practical approach to performance improvement was used by the American Society of Breast Surgeons to create a toolbox of options to reduce lumpectomy reoperations and improve cosmetic outcomes.

The importance of surgical margins in breast cancer

Achieving negative margins with "no tumor on ink" is an appropriate goal in breast conserving therapy (BCT). Wider margins do not decrease recurrence rates, and re-excision in patients with microscopic positive margins is warranted. Several strategies exist to increase rates of negative margins, including techniques to improve tumor localization, intraoperative assessment of margins and oncoplastic techniques. Negative margins should be the goal of BCT, as this will improve both local control and long-term survival.

Digital mammography versus digital breast tomosynthesis for detection of breast cancer in the intraoperative specimen during breast-conserving surgery

PURPOSE

To compare the diagnostic ability of specimen radiography using digital mammography (DM) and digital breast tomosynthesis (DBT) for detecting breast cancer and evaluating its extension in the intraoperative specimen.

METHODS

Sixty-five specimens from 65 women (median 62 years; range 34-86) obtained during breast-conserving surgery were prospectively investigated. Specimens underwent DM (25-40 kVp, 12-322 mA s) and DBT (25-34 kVp, 13-137 mA) in two orthogonal planes, anteroposterior (AP) and latero-lateral (LL). Images were interpreted by a radiologist to detect invasive lesions and their extensive intraductal components (EIC) or ductal carcinomas in situ (DCIS); afterwards, they were compared with histopathological findings.

RESULTS

In AP views, 96 % of the invasive lesions were detected by both the methods. Of the EICs, 55 and 65 % were detected by DM and DBT, respectively (P = 0.61). Of the DICSs, 31 and 38 % were detected by DM and DBT, respectively (P > 0.99). In LL views, 71 and 13 % of the invasive lesions were detected by DBT and DM, respectively (P < 0.0001). Of the EICs, 42 and 10 % were detected by DBT and DM, respectively (P = 0.0078). Of the 13 DCISs, 42 and 8 % were detected by DBT and DM, respectively (P = 0.32). The whole lesion and contour could be delineated in 45 % by DBT and in 6.2 % by DM (P < 0.0001).

CONCLUSIONS

DBT could detect breast cancer more accurately than DM in LL views, indicating its potential to more precisely diagnose vertical invasion.

Intra-operative digital specimen radiology reduces re-operation rates in therapeutic mammaplasty for breast cancer

BACKGROUND

The aim of this study was to evaluate our experience with intra-operative imaging of therapeutic mammaplasty specimens at Edinburgh Breast Unit.

METHODS

A retrospective review was performed of patients who underwent therapeutic mammaplasty in Edinburgh Breast Unit between 2007 and 2013 who had intraoperative specimen radiography.

RESULTS

98 (100%) patients who underwent therapeutic mammaplasty for breast cancer had intra-operative imaging using the faxitron(®) system. 3 out of those 97 (3%) patients had a re-operation because of positive margins confirmed pathologically on cavity excision specimens, but only 1 out of 3 (1%) patients had residual breast cancer present within the re-excision specimen. None required mastectomy. Median age was 58 (range 34-81). Median follow up was 3.1 years (range 6 months - 5.5 years). There was no local recurrence or conversion to mastectomy in this group.

CONCLUSION

Complete excision rate in patients who had intra-operative imaging during therapeutic mammaplsty procedure was 97% in our group. Faxitron(®) system is a useful adjunct in helping to achieve low incomplete excision rates.

Intra-operative guidance: methods for achieving negative margins in breast conserving surgery

The increasing incidence of breast cancer and advances in detection of small, impalpable cancers presents increasing challenges for the modern breast surgeon. Accurate localization and excision with adequate oncological margins to reduce loco-regional recurrence rates whilst minimizing volume deficit and maximizing aesthetics remains the "gold standard." We review the current techniques available and the developments within this field.